Allotoca dugesii

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Allotoca dugesii
Allotoca dugesii
Original Description: 

  BEAN, T. H. (1887): Descriptions of five new Species of Fishes sent by Prof. A. Dugès from the Province of Guanajuato, Mexico. Proceedings of the United States National Museum 10: pp 370 - 375

Etymology: 

  The species is named after A. Dugès, who settled in Guanajuato, organized field trips to collect animals and sent this fish to Bean for description.

Holotype: 

  Collection-number: United States National Museum, Cat. No. USNM-37831.

  The Holotype is an adult female of 60mm standard length (a second female of 64mm standard length had been deposited under the same collection-number, but the first in the description mentioned has to be named as the Holotype), collected by A. Dugès, collection-date unknown.

English Name: 
Bumblebee Allotoca
Mexican Name: 
Thiro
Synonyms: 

Fundulus dugèsii   Bean, 1887

Adinia dugesii   Jordan & Evermann, 1896

Zoogoneticus dugesii   Meek, 1902

Allotoca vivipara   de Buen, 1940

Karyotype: 

  The Karyotype describes the number and appearance of chromosomes during the phase of condensation, classified by the position of the centromere (Levan et al., 1964).

The following abbreviations are employed:

 

M = large metacentric chromsome (a result of Robertsonian fusion)

m = small metacentric chromsome (centromere at medium position)

sm = submetacentric chromsome (centromere at submedian position)

smst = submetacentric-subtelocentric chromosome (continous series)

st = subtelocentric chromosome (centromere at subterminal region)

stt = subtelocentric-acrocentric chromosome (continous series)

t = acrocentric chromosome (centromere at terminal region)

 

The Karyotype of Allotoca dugesii, following Uyeno, Miller & Fitzsimons, 1983:

2n = 26    22M/ 2smst/ 2st  

Size: 
The maximum known SL is 63mm (Miller et al, 2005).
Terra typica: 

  The Holotype comes - following Bean -"probably from streams belonging to the Pacific slope of the Province Guanajuato".

Status after IUCN: 

  not assessed

Status following other sources: 

  Status: Endangered

  Population development: Declining since 2000 

Distribution and ESU's: 

  This species comes from the Pacific Slope and inhabits the basins of the ríos Lerma-Grande de Santiago, the Río Grande de Morelia and the lagos Yuriria, Cuitzeo, Pátzcuaro and Zirahuén from Jalisco to Michoacán. It is also reported from the endorheic Laguna San Marcos and the Lago de Magdalena west of the Lago de Chapala in Jalisco, but fish from this area should belong to Allotoca maculata.

 

  ESU ist short for Evolutionarily Significant Unit.  Each unit expresses an isolated population with different genetic characteristics within one species.  ESU's can be defined by Molecular genetics, Morphology and/or Zoogeography and help in indicating different phylogenetic lineages within a species. The abbreviation for an ESU is composed of three letters of the genus, followed by the first two letters of the species name and an ongoing number in each species.

 

  Allotoca dugesii is distributed over a wide range and so we are able to distinguish several ESU's. The first one is Altdu1 and encompasses fish from the Río Duero west including the Lago de Chapala and the ríos Santiago and Verde.

  Altdu2 is in use for populations north of the middle Río Lerma, especially the ríos Turbio and Guanajuato.

  The fish from the Lago de Cuitzoe basin up to the Lago de Yuriria are named Altdu3.

  The fourth and last ESU, Altdu4, encompasses fish from the Pátzcuaro and Zirahuén lakes

Habitat: 

  Allotoca dugesii lives in lakes, ponds and streams and prefers in general depths of less than 1.3m. It can be found over clay, mud, sand, gravel and rocks. Vegetation can usually be found, but is absent sometimes. When vegetation is present, it consists of Nasturtium, Ceratophyllum, Potamogeton, Eichhornia and green algae. The currents are none to moderate, but sometimes strong, too. The water is either clear to murky or muddy.

Colouration: 

  Allotoca dugesii is a species with a remarkable sexual dichromatism and dimorphism. Both sexes have the upper body olive (intermingled with silver) and the lower body silvery. The males have a dark midline from the corner of the eye to the base of the caudal fin. Females have this line interrupted partially. The base of the fins can exhibit yellow or orange colouration. Females show four to eleven dark vertical stripes with blue areas along the flanks. Bean described these stripes (in spirits) as "five or six dusky bands, the widest somewhat greater than the length of the eye. On of these bands is placed under the anterior half of the dorsal". The operculum is silvery coloured.

  At least in one population (Rancho el Molino) individuals can show dark black blotches on the sides, similar to blotches seen in Skiffia multipunctata, but not so prominent.

Biology: 

  Meek reported young born in the last week of May (1904). A 13mm individual was taken on 27 February (water temperature 13°C) near Presa Coplaita, northwest of Guadalajara, which indicates that the reproduction may occur over a much longer period. Females were pregnant with eyed embryos on 4 March (water temperature 10°C) near Undameo in the Río Morelia basin.

Diet: 

   The teeth are slender conical, in a double row, of which the outer is enlarged and firmly attached. Combined with observations in captivity, this leads to the assumption of a more carnivorous diet, probably hunting small water invertebrates and insects from the water surface.

Remarks: 

  Allotoca dugesii is the species with the widest distribution among the genus Allotocabut according to its sneaking life, little is known about its life-history. However, it seemed to have disappeared from more than 50% of its historically known distribution range, finding refuges in the Lago de Cuitzeo basin, the Patzcuaro basin and few locations nearby north of the Lago de Cuitzeo. Despite of this, in 2010, Czech and Slovakian hobbyists have been successful in sampling fish in the Río Santiago, so this species might still be present in some areas, where it has been thought of having disappeared.

 

  Though the resemblance of Allotoca maculata, Allotoca goslinei is recognized as the nearest relative by several authors and according to results of phylogenetically researches.

 

  In the endorheic basin of Lago de Pátzcuaro, this species lives sympatric with Allotoca diazi.

 

  Fernando de Buen described in 1940 Allotoca vivipara from the Lago de Pátzcuaro. Smith and Miller examined the holotype and additonal material in 1987 but found no significant differences between these fish and Allotoca dugesii. Therefore, they agreed with the opinion of Aurelio Solórzano (pers. comm. to Miller in 1967) that Allotoca vivipara has to be seen as a synonym of Allotoca dugesii.

Husbandry: 
  Looking on the biotopes of Allotoca dugesii, they suggest the species may prefer a habitat with moderate to swift current, structured with gravel, rocks, roots, branches, fallen leaves and river bank vegetation. Fry is eaten in most of the cases, but it may depend on the quantity and quality of food and on the number of space to hide. When several different stages of juveniles occur, fry may be neglected, so it makes sense to add separate brought up fry to the group with a size of 1.5 or 2cm to provide these stages and get a flock breeding colony.

 

 The recommended tank size is at least 100 liters, bigger ones with a generous base and little height (25cm are enough) are better for sure. With rocks and vegetation in the corners and backsinde of the tank well structured tanks combined with some roots and/ or wood seem to do best with this species. The current should be moderate or swift. 

 

 In the wild, the species seem to feed from small or middle - sized invertebrates like bloodworms or insect larvae, so feeding with similar food, Daphnia, Mysis and other food from animalistic sources will be best for this predatory fish.   

 

 Concerning water quality, this species is in need of greater water changes (60 - 80% every week) like most of the Goodeids, especially river and spring inhabiting species, so an automatic water changing system can be helpful. Otherwise, in combination with constant temperatures higher than 24°C, fish may get sick, lose resistance against diseases and age too fast. So for keeping the strain healthy and strong, give the fish a rest during winter time with temperatures lower than 20°C for 2 or 3 months so they stop producing fry. Allotoca species can be kept down to temperatures of 15 or 16°C without problems for months, some species even lower. In spring, when the temperature slowly increases, they will start spawning at 20 or 21°C and won't stop until it gets colder again or when it gets too warm (25°C?).

 

 This species is doing very well when is kept in the open from spring to fall, starting when the temperature exceeds 15°C water temperature and cold periods are no longer expected. During the warm summer, reproduction will stop and may occur again in fall. Bring the fish in before the temperature goes below 10°C water temperature and keep them cool for the first days, then slowly raise the temperature but try to stay below 20°C over the winter time.

 

First Describer: 
(Bean, 1887)
Photos: 

 

Image 1: female from Rancho el Molino

Copyright by Markus Heussen

Image 2: male from Rancho el Molino

Copyright by Markus Heussen

Image 3: fresh born fry

Copyright Image 3: Markus Heussen

Image 4: female from La Maiza

Copyright by Omar Domínguez Domínguez

Image 5: male from La Maiza

Copyright by Omar Domínguez Domínguez

Image 6: male from Colonia Guadalupe

Image 7: female from Colonia Guadalupe

Images 8 and 9: male from the Río Santiago

Image 10: female from the Río Santiago

Image 11: male

Images 12 and 13: male

Images 14 and 15: female

Image 16: female from the Río Santiago

Copyright: Anton Lamboj

Image 17: young male from Rancho el Molino

Copyright: Anton Lamboj

Images 18 and 19: females from Rancho el Molino

Copyright: Anton Lamboj

Images 20 - 22: different males at different ages from the Río Santiago

Copyright: Anton Lamboj

Images 23 and 24: females from the Río Santiago

Copyright: Anton Lamboj

Images 25 and 26: male from the Río Santiago

Copyright: Anton Lamboj

Image 27: male from the Río Santiago

Copyright by Wolfgang Gessl (www.pisces.at)

Image 28: female from the Río Santiago

Copyright by Wolfgang Gessl (www.pisces.at)

 

 

 

Image 1: female from Rancho el Molino
Copyright by Markus Heussen
Image 2: male from Rancho el Molino
Copyright by Markus Heussen
Image 3: fresh born fry
Copyright Image 3: Markus Image 1: female from Rancho el Molino
Copyright by Markus Heussen
Image 2: male from Rancho el Molino
Copyright by Markus Heussen
Image 3: fresh born fry
Copyright Image 3: Markus Heussen